Research And Application Of SQLite Database Based On Qt/Embedded

With the development of embedded technology and the popularity of smart mobile devices, the demands of users for data processing and management have been improving. An effective management for the data of the embedded products is required by more and more users, and embedded Database is a very effective tool.Embedded database could be often used in the embedded devices such as PDA, smart phones, automotive equipments and so on, where the memory is very limited. Some subjects such as how to use the embedded database for the intelligent terminals, how to make the embedded database use the limited storage resources effectively are important direction of study on embedded system.Currently, the most embedded database systems use B~+ tree indexing mechanism. It has advantage of high efficiency and being able to process operations on the records of B~+ trees randomly and sequentially. It can maintain the dynamic balance of the tree. However, the B~+ tree indexing mechanism has a fatal disadvantage for wasting storage space capacity in the embedded systems.The statistic shows that B~+ tree indexing mechanism guarantee only about 50% storage utilization.The main task of the paper is to improve the index mechanism of the B~+ trees in SQLite. Combined with the Qt/Embedded, the improved SQLite is used to design and implement the electronic dictionary in the intelligent terminal. Firstly, the Qt/Embedded framework and architecture as well as its communication mechanism - signal and slot were studied in the paper. Secondly, SQLite architecture, implementation idea of the development technology the index mechanism were analyzed, which the index mechanism was improved based on. Finally, the index mechanism was migrated to ARM-Linux platforms, and it is proved that the improved SOLite heightend the utilization ratio of memory space by experiment. The design and implement of the electronic dictionary in Intelligent Terminal was one of the applications based on the improved index mechanism. The development of the electronic dictionary, the design of operation environment and the interface and the implementation of the electronic dictionary were introduced in the paper. Meanwhile, the establishment of the database files and the connection of SQLite and Qt/Embedded, the realization of Qt/Embedded applications and, the process of electronic dictionary added to the Qtopia platform were also described. Finally the key problems and solutions in the development process were analysedin detail.